


Avatar- the Fallen Nations

by Trigirl200



Category: Avatar: The Last Airbender, 僕のヒーローアカデミア | Boku no Hero Academia | My Hero Academia
Genre: Aizawa Shouta | Eraserhead is So Done, BAMF Bakugou Katsuki, BAMF Midoriya Izuku, Bakugou Katsuki Swears A Lot, Bakugou is emotionally obtuse, But I bleeped it out, Deku is the Avatar, Everyone can bend elements, F/M, M/M, Protective Bakugou Katsuki, Ships to Be Decided Later, all four nations are at war, wacky spirit world schenanigans
Language: English
Status: In-Progress
Published: 2020-07-03
Updated: 2021-02-06
Packaged: 2021-03-04 19:41:25
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 4,672
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25041826
Author URL: https://archiveofourown.org/users/Trigirl200/pseuds/Trigirl200
Summary: Izuku Midoriya never asked to be the worlds last hope for peace, and yet here we are. After an attempt to use the Avatar to endorse the Fire Nations attacks, Izuku and his best friend are rushed towards the Earth kingdom to begin his training. A surprise attack ruins this plan, and after a disastrous use of the Avatar state, they are encapsulated in stone for two hundred years. The disappearance of  the Avatar results in a two hundred year war involving all of the nations. Upon re-entering the world, Izuku must find a way to end the war and finally restore peace to the nations.
Relationships: Bakugou Katsuki/Midoriya Izuku
Comments: 2
Kudos: 18





	1. Everything changed when the Fire Nation attacked

**Author's Note:**

> Ok, before you begin this story, let me explain some things. In this AU, there is not Aang, or Sakka, or any of the original Avatar characters. Izuku and Bakugou are about 15 years old and Izuku has know he is the Avatar for about two years. They are raised in the Fire Temple and the Fire Lord wants to use the reputation of the Avatar to endorse a mass attack with the power of the comet. Hide is Izuku's dragon companion, and you say his name like He-day. I think that's all for now, enjoy!

"Deku, get the h*** up."

Izuku started out of his sleeping pad with a harsh shove, courtesy of his best friend and fellow fire monk, Bakugou Katsuki. He groaned and sat up, rubbing the sleep from his eyes.

"Kacchan? You do remember what happened last time you woke me up, right?" He looked up, expecting to see Bakugou's death glare aimed right at him. What he actually saw was even more terrifying than that.

Bakugou looked pale and was breathing hard. His eyes were wide in panic and he kept looking around wildly. Immediately the playful smirk fell from Izuku's lips. He lept to his feet and joined his friend at the window.

Outside of the Fire Temple, a massive battalion of Fire Nation soldier surrounded the walls. The head monks were standing atop the walls, pushing back the oncoming attacks. Even with all the power of the monks, Izuku knew it was only a matter of time before the temple was completely over-taken. He turned to Bakugou, face deadly serious. 

"What happened?" Bakugou finally tore his attention away from the battle field outside. He tossed Izuku his outer robe and began walking towards the door.

"Fire Lord Hiro ordered an attack on the Earth kingdom. They struck during the night and conquered one of their major cities." Izuku groaned, running a hand down his face.

"Let me guess, they want the Avatar to vouch for this attack even when I specifically told the lord and his advisors I would never support them?" Bakugou shot him a tense smile.

"You guessed it. The monks want us to flee to the remaining Earth kingdom strongholds so you can learn earth bending and we can put a stop to this idiotic attack."  
The ground pitched violently, sending Izuku tumbling into Bakugou. The whole temple shook as explosions rattled against the walls. Izuku met Bakugou with panicked eyes before pushing away from him and made his way over the rubble.

"We have to get to Hide. He's the only way to get above the soldiers." Bakugou nodded and they worked their way through the crumbling halls. Theey stumbled into a wide courtyard where another figure was bracing themselves against a pillar. When Izuku caught sight of them, his eyes widened happily.

"Monk Yagi!" the man turned to face the two young students, eyes widening in joy.

"Young Midoriya! Young Bakugou! It's good to see you haven't left yet!" Izuku rushed to his side, Bakugou following closely behind.

"Are you coming with us to the Earth temple?" The skinnny monk nodded. 

"The guardians decided I should accompany you to ensure your safe arrival." Izuku grinned and nodded.

"We're glad to have you with us." Beside him, Bakugou cleared his throat loudly.

"I hate to break up this touching moment, but we are under attack right now." Izuku let out an irritated puff of air as he pulled out a small black whistle.

"Don't worry Kacchan, Hide can get us out no problem." He blew into the whistle, and while they couldn't hear anything, on a neighboring mountaintop, a large black dragon lifted his head.

Izuku kept his eyes trained to the sky as he tucked away his whistle. Bakugou pulled him close to his side as the temple began shaking once again. 

"Your d*** lizard better hurry up and get his a** over here Deku." Izuku's eyes never left the sky as he responded to his friend.

"He's a dragon Kacchan, and when has Hide ever let us down?" The sky was so full of smoke and ash that it was impossible to make anything out. tiling was sliding off the edge of the roof with every tremble of the walls. After a few tense moments, that felt like hours, a bone-rattling roar echoed over the temple grounds. Hide descended from the smoke like a living shadow, they teardrop shaped marks under his eyes seemed to glow through the grey clouds. Izuku rushed over to his head eagerly.

"Hide! perfect timing there buddy!" Bakugou scoffed as he helped Monk Yagi onto the proud beast's back.

"Cocky lil' s*** just had to make an entrance, didn't he?" Izuku shook his head at Bakugou as he took his place behind Hide's spikes.

"He's here now, let's just get out of here." With a sharp whistle, Hide spread his wings and launched them all into the sky. Although he would forever deny it, Bakugou still hated the feeling of the ground getting farther and farther away.

Hide flew over the battlefield easily, the thick smoke covering just how horrible the scene really was. After perhaps an hour of flight, the Earth kingdom boarder came into view; and with it came the dreaded sight of more fire nation troops laying in wait just shy of the unmarked boundaries. 

Izuku tightened his grip on Hide's reins, a drop of sweat beading down his face. Below them, the soldiers began loading their catapults. 

The first volley of flaming loads was easy enough to dodge, but as more of the burning projectiles filled the sky it became more of an issue. Hide twisted in midair, desperately trying to keep his wings from being hit. After one particularly close shave, Bakugou found himself being jerked off of the back of the struggling dragon.

Izuku whipped around just to see Bakugou falling into the smoke below. Without hesitation, he directed Hide in after him. Hide tucked his wings in, picking up speed as they shot towards the ground.

Bakugou was only feet below them now, twisting wildly in an attempt to slow his fall. From somewhere above, he thought he heard his own name. He managed a glance over his shoulder to see Deku desperatly reaching for his hand. The ground was getting dangerously close, so Hide tried to twist out of the sharp dive. Izuku barely managed to tug Bakugou back onto Hide before they were roughly crashing into the scorched earth. 

Dirt flew up into the air, joining the cloud of swirling smoke around them. Hide dug his claws into the damaged soil to slow their skid. As they came to a stop, all of his passengers were launched from his back. Izuku winced as he tried to put pressure on his ankle. Monk Yagi and Kacchan had fallen closer to Hide, but Izuku had flown a bit farther into the smoke.

He coughed harshly, trying to pull himself to his feet. He could hear heavy footsteps coming nearer and nearer as shadowy figures appeared all around the small group. Somewhere in the distance, he could hear Kacchan and Monk Yagi calling for him, but his head was spinning to much for him to make out their location. 

Bakugou raced towards him, sliding to his knees by Deku's side. The smaller boy was struggling to his feet, one hand bracing his head. Monk Yagi reached their side just as the figures burst into clear view. He immediately began bending a defensive circle around the boys. 

He turned to look at Bakugou over his shoulder.  
"Get young Middoriya out of here! You need to make it to the Earth temple." Bakugou lifted his head to glare at him harshly as he tried to tug Izuku away from the flames.

"What about you old man? We're not leaving you!" Yagi shot him a sad smile and shoved them towards Hide. 

"I'm afraid this is one order you must obey." The boys struggled to their feet, a barely conscious Izuku leaning heavily against Bakugou as they made their way back to Hide. 

More soldier surrounded Yagi as he fought gracefully with his flames. Bakugou managed to lug a struggling Izuku back onto Hide and had just turned back for Yagi when disaster struck.

One of the soldiers managed to redirect Yagi's fire back onto him, sending him tumbling to the ground. In that instant, another soldier leapt forward, sinking their spear directly into his chest. 

Izuku's eyes widened in horror as his mentor and father figure hit the ground. His head tilted upwards to give the boys one last shaky smile before his eyes went dark. Distantly he could hear the agonized yell coming from his own throat, but his own body seemed on an entirely distant plane than his mind. His hands were clenched in shaky fists, eyes never moving from the monks bloody corpse. 

He wasn't even aware of his eyes beginning to glow with a harsh blue light. Bakugou leaned away from him as a surge of ancient power filled his limbs. Without thinking, a harsh gale swirled through the smoky field; clearing the view in an instant. Izuku began to levitate, lifted by surges of swirling air. With a wave of his hand, the surrounding enemies were thrown roughly into the fleeing smoke clouds. Another wave brought the flaming catapults collapsing in on themselves.

Bakugou desperately called out to his friend, trying to pull him from that state; but Izuku didn't seem to hear anything. Stone began piling up all around them, creating a giant mountain around them. Bakugou felt a strange cool sensation creeping up his legs. He looked down in panic to see grey stone climbing up his body. 

He thrashed and cried desperately, but the stone continued it's way up his body. The last glimpse he had before the cool stone completely entombed him was his best friend lowering back onto the stone back of Hide, arms and legs bent in a meditative stance, eyes just beginning to dull. 

On that day, the Avatar, the worlds symbol of peace, appeared to vanish without a trace. The mountain that appeared mysteriously was all that remained of the Avatar for almost two hundred years. It became know as a sacred place, and remained untouched for the much of those passing centuries. As time passed and the wars continued, hope of the Avatar's return began to dwindle; and in it's place rose a new organization, dedicated to sowing more chaos. 

This organization was known as All for One, and it existed to try and create one glorious kingdom, with all of the nations under the rule of their twisted leader, Shigaraki Tomura.


	2. The Boy in the Mountain

**Summary for the Chapter:**

> OK! We are back in business! This chapter will be introducing two of my OC'S! Also, it gets a bit gory towards the end, so if you have issues with that, you might want to breeze past the last few paragraphs. I can't computer and I don't think the sketches I tried to embed last time worked, but if anyone wants it, I will try to find a way to add that in, and a few pictures of my OC's! Let me know if anyone wants to see those, and enjoy the chapter!

Believe it or not, a lot can happen in two hundred years. What had started out as a pretty one-sided battle quickly got messy as alliances were made and broken just as quickly. The four nations splintered, with radical groups branching off while whole cities ran off to try to disappear into the few unclaimed areas. As the world fell to chaos, the mountain remained virtually untouched.   
It became a pathway for refugee's fleeing any pursuers. Most people hesitated to step foot there, but to anyone desperate enough, it was a sure passage into a vast forest area where a large refugee camp had sprung up. The mountain was rough, with an unpredictable landslides and shifting paths making it almost impossible to venture over. But more alarming, for whatever reason, bending did not work on the mountain. Only the truly desperate or insane would even consider crossing the mountain. 

However, that did not mean it was unused. Two young siblings had been left on the mountain, and had grown up clambering across its crevices. Their names were Kaze and Arashi Achikita. They were twins, alike in all manner except their bending abilities. Kaze took after their mother, mastering the ways of air bending. Her brother took after their father, bending water as easily as breathing.

They were abandoned on the strange mountain when they were about four. From then on, they have been running groups of refugees across the mountain range, to the safety of the forest. It was on one of those many trips that they met Shota Aizawa. Aizawa ran an espionage ring all across the old nations. To anyone searching for peace, he had the information to guide you. 

Aizawa quickly took to the kids; supplying them with troop movements and information of life beyond the mountain range. When he eventually moved on, he set up a communication method to keep the kids involved in the ring. 

For years, all remained about as calm as you can find in a war zone. But that all changed on the day earth bending legend, General Giran arrived back in his home city of Musutufa, at the base of the mountain.

The day started off ordinarily enough, but before noon had broken, fleets of soldiers were flooding the streets as the General and his advisors clattered down the street on their mighty steeds. He ignored the clamoring citizens as he made his way towards Musutufa's patriarch's home. After dismounting, he strode confidently into the front hallway.

He shoved past the frantic servants, marching directly to the Patriarch's meeting hall. The poor man looked stunned as the General stopped directly before him. He smirked before speaking in his rough, gravelly voice.

"I'm told that you have been allowing refugees to slip right past you, apprehended." The poor man gulped, trying to hide his shakey hands in his robes. "Would you like to explain why that is, Patriarch Volding?" 

"Sir! We do not have the manpower to stop the travelers! They disappear into the foothills before anyone can catch up to them!" Giran leaned forward smugly.

"Is that so? are you saying you are not up to the job then? You know Lord Shigaraki would be more than happy to replace you if you find this assignment to challenging." Volding gulped, casting his eyes downwards. 

"I think you will find us more than capable for this job. You are absolutely right. We have allowed those cowards to dishonor us for to long." Giran grinned, leaning back on his heels as he blew a puff of smoke from his cigaret directly towards the cowed man. 

"That's what I like to hear pops. I expect those little rats to be cleared out of that mountain by tomorrow at the latest." The old man jolted straight up.

"Tomorrow? You can't possibly expect-" He was stopped as the General grabbed him by the throat.

"I said tomorrow gramps, will that be an issue for you?" The poor man gasped for air around the tight grip.

"N-no, no problem General. You have my word, we will take care of the situation." The General grinned viciously, patting the man harshly on the cheek and letting him slide to the floor.

"Good. Now take care of it. I'll pass the word on the the Lord when you have finished your task." He strode towards the door, pausing in the doorway to look over his shoulder. "I don't think I need to tell ya how disappointed his Lordship will be if you fail this little assignment."

As he left, silence rang out in the meeting hall. After a few stunned moments, Volding shook himself off, leaping to his feet to summon the few troops their little city had. The fully assembled battalion added up to on a pitiful hundred and fifty men. He sweat nervously as he look across the field of waiting men. Most of them were to old or to young to enlist in the actual ranks of the military, leaving only weak and inexperienced volunteers to protect the city.

"Soldiers. We have been given a mission from Lord Shigaraki himself." At his words, the fidgiting ranks stilled, everyone anxiously hanging on his next words. "We have allowed refugees to pass through here for to long. Our great ruler has commanded we put a stop to this! Today, we raid the mountain, and finally end this disgraceful act!" 

Most of the older men looked about worriedly, but the younger boys cheered mightily. The Patriarch turned back towards his house as the troops rallied around their captains. They had no idea what they would be facing with this task.

The raid was to be launched at first light. Since the mountain didn't allow bending, the men marched up the winding footpaths in full armor and heavy shields and spears. 

From the top of the mountain, Arashi Achikita watched sleepily as the procession tried to climb higher. Tried being the keyword here, as the footpaths kept collapsing under all the weight of the battalions. Already, over half of the group had tumbled back to the base of the mountain and remained unmoving there. He leaned back against a tree as his sister joined him. She leaned against his shoulder, yawning widely.

"What are the odds that we will actually have to interfere with this mess?" He snorted at her tone. 

"Please, if anyone makes it up to meet us, I'll fix up the campsite for a month." She shot him a mischievous little smirk.

"Oh? you may have spoken to soon brother-dear." He frowned and leaned forward to get a better look.

"What do you- oh, damn. Look at that, someone has a brain down there." 

They watched as a small group of the advancing group broke off from the main group. It only consisted of about five soldiers, but they had removed most of their armor and weapons to decrease their weight on the shaky trails. 

Kaze laughed and smacked his shoulder. "Looks like we might be getting some visitors today. Don't forget to gather up the firewood!." He groaned dramatically, smacking his head against the tree trunk behind him as Kaze flounced away.

Even with the decreased weight, it still took the small group hours to climb the mountain. By that point, the men were a sweating, exhausted mess. They hadn't found any sign of the refugees or anyone else living atop the mountain. As they stumbled into a clearing, the men slumped to the ground. One of them, Kirishima Eijiro, tipped his head to the sky with a sigh.

"Shouldn't we have found something by now if anyone was here?" He looked over tiredly at his companions. They all looked beat up, most of the group were limping along on sprained ankles, or nursing various bruises and scrapes.  
\   
"C'mon guys! You heard what Father Volding said! Lord Shigaraki is trusting us to take care of this! We can't let him down now!" Most of the group just groaned at his words. He felt himself start to droop slightly.

Suddenly, a voice rang out from the trees above them.

"Lord Shigaraki, huh? I was wondering how long we would have before that crusty freak decided to get up in our business." 

Kirishima shot to his feet, looking around wildly for the source of the voice. Before he could find it, another voice sprung up from the shadows. 

"You know what a sore loser that guy is. Can't you just see him throwing a little baby tantrum?" 

Kirishima practically growled as he spun around searching for the voices. The shadows swirled around the clearing, throwing off any sign of the speakers.

"Alright, come out and fight! You can't just insult the grand ruler and expect to walk away like that!" A gentle voice rang out from right behind him.

"Who said anything about walking away?" Though he would never admit it, Kirishima just about lept out of his skin. He spun around, nearly tripping himself, only to see a small blond haired girl leaning towards him. Upon first glance, she looked harmless. She was about half a foot smaller than him, and looked like a strong breeze would send her flying. She had long silvery blond hair held back from her face by a leather band encircling her head. It was the look in her stormy grey eyes had him second guessing her strength. 

While he was distracted sizing her up, someone dropped from the branch above them, landing directly on his shoulders, sending Kirishima tumbling to the ground. The second body remained perched on his chest, pining him to the ground. He opened his eyes to see a grumpy pair of grey eyes glaring right back at him.

"Why couldn't you losers have stayed with your idiot captains? I lost a bet because of you." 

The furious look almost had Eijirou pleading for forgiveness before he remembered what he was here for. He chanced a quick look around the clearing. His men had lept to their feet and stood nervously clutching their spears, unsure of how to react. The small girl stood casually, one hand on her hip as she watched the boy pinning him to the ground. The strange boy was still looking grumpily down at him.

"Well? Are you going to keep staring at us, or are you looking for a fight?" The girl slapped a hand against her forehead at her brothers words.

"Not the way I would have phrased that, but you raise a valid point Rashi." She looked around the clearing, clearly sizing up her opponents. "Well? Whose first?" 

The men seemed stunned for a few seconds, but finally a tall, broad shouldered man stepped forward. The girl grinned as she fell into a defensiveness stance. Kirishima studied her in confusion. She didn't appear to have any weapons, and she barely came up to her opponents chest. She should be at a disadvantage, but she seemed just as comfortable as before.

The man launched himself forward, spear jabbing out before Eijirou could even blink. To his surprise, the girl spun, completely dodging the jab, and landing a harsh kick against the man's ribs. Her movements seemed to blur as she lept around the man, always just our of reach. 

Seeing their companion struggle, the other three men in the clearing rushed forward, joining the fight with little success. Bending might not work on the mountain, but the girl seemed to fly as she lept over her opponents. However, it was three against one, and after a while, she made one fatal mistake. 

As she landed on the ground, she stumbled a bit, leaving herself open for just a moment. The smaller man who had been traveling with them, Shiro, struck in that instant. His spear lodged itself right below her ribs. The girl fell back with the force of the blow, curling around the spear as she hit the ground. 

Her brother was up in an instant, running towards his sister with an angry cry. Emotion practically sizzled from his eyes as he glared at the armed soldiers. Kirishima pushed himself to his feet, studying the scene before him. 

Luggar, a big and brash man stepped forward with his spear leveled with the boys face. Instead of a look of fear, a look of pure rage flooded across his face. A strange wind ripped across the clearing and the clouds above darkened ominously. Kirishima felt his eyes go wide as both twins looked up with glowing eyes.

The smell of ozone flooded the area as the wind and storm grew harsher. A bolt of pure energy arced across the sky, slamming into a wall of stone just behind the men. The earth itself began to crack, sending huge portions of land sliding all the way down to the base of the range. All the while, the twins remained unmoving, clinging to each other as the world crumbled around them. Glowing eyes never breaking contact with Kirishima's own red orbs. 

One by one, the men were pulled into the cyclone building in the center of clearing. They cried out as growing monster launched them into the crackling sky. When It was just the three of them left in what remained of the clearing, the whole mountain seemed to erupt.

For a few terrifying moments, Kirishima couldn't tell if he was falling or rising into the air. After a few heart wrenching twists in the air, he saw teh ground rising up to catch him. Instinctively, he reached out with his bending, creating a hard rock shell to protect him from the fall. 

When he came to a stop, he looked up in horror. The whole mountain had disappeared, leaving only piles of rubble and scorch marks. This however wasn't what had him looking on in shock. The twins were perched right beside a giant glowing orb. 

As the light from the orb began to dim, the outline of what looked like a dragon and two young boys came into view. Finally the blue light died out and the who earth seemed to breath a sigh of relief. 

Both the twins and the strange figure collapsed, falling over onto one another. Kirishima rushed forward instinctively, righting the twins before they pitched forward.   
After a moment, Arashi seemed to come back to himself, tugging his unconscious sister away from the earth bender. Together they looked on to the three figures that were only just beginning to move.

The dragon curled itself around the two boys, nudging gently at the curly haired one. He jolted, reaching towards his spiky haired blond companion. The two boys looked around wildly and whispered fiercely to each other for a moment before their gazes fell on the three beat up teens gazing up at them. The blond boy glared before leaping down towards them.

"What the hell happened here?" He glowered so fiercely that Kirishima couldn't even find the words to say to call him down. Luckily Arashi didn't seem to have that problem.

"Why don't you tell us who the hell you are first? How long have you been inside that mountain?" The blond seemed confused. His dark haired friend came up from behind him. 

"Maybe we can help each other out here, The last thing I remember was being enclosed in stone, so how long has the mountain been standing?" Arashi frowned in confusion.

"What do you mean? It's been here for at least two centuries." Both boys went pale. The angry blond spoke up again.

"What happened when the fire nation attacked the night of the comet?" Arashi snorted in surprise.

"The night of Sojin's comet? The world went to shit. That was the night the Avatar vanished."

Before any more questions could be asked, a wet cough rattled out of the girl. She shivered as she snuggled deeper into her brother's side, spear still embedded in her side. Without a word, her brother stood, arms gently cradling her, so as not to move the spear.

Her head rolled limply against his shoulder as he began striding across the rubble. That was what snapped Kirishima from his shock. He rushed after them, catching the boy by his arm and yanking him around to face him.

"Wait! you can't just rush of with her in that condition!" Arashi whirled around, rage once more flooding his features. 

"Oh? You trying to finish the job or something?" Kirishima stumbled back in shock.

"NO! I'm trying to help you! She's not going to make it far in her condition. You shouldn't be moving her." Arashi opened his mouth to speak again, but another voice interrupted him.

"He's right. You need to stabilize the wound before you try to move her." The dark haired boy rushed over, instructing Arashi to lay her on the ground. 

The blonde joined him, moodily settling on the other side of thee girl. He held her down as the curly-headed boy swiftly yanked the spear tip out of her side. The girl startled awake with a choked sob of pain. Arashi lunged forward, only to be held back by Kirishima. With a still struggling Arashi in his arms, he watched in a morbid fascination as the blond shoved a piece of fabric into her mouth and continued to hold her down as the dark haired boy raised a flaming hand to the wound. 

She struggled violently, screams muffled against the fabric. After a few torturous moments, she fell still. Once again unconscious against the pain.As the strange boys baked up, Kirishima let his arms go lax, releasing Arashi to rush towards his sister. 

He looked up at the strangers with tears ofrage and confusion streaming down his face.

"Wh-who are you two?" The boys shared a deep look before the dark haired boy responded.

"This is Bakugou Katsuki, and I am Midoriya Izuku. I am the Avatar.

**Author's Note:**

> Alright fellas, I have some rough sketches of what I think Deku and Bakugou would look like within this AU. It didn't turn out quite how I wanted it to, but at least you an get a general idea of their outfits.
> 
> https://drive.google.com/file/d/1fCAcSkKyqiP6vqpCYU5rThIVXund3gTR/view?usp=sharing
> 
> https://drive.google.com/file/d/1vV6lrLM_f_miB52DkQXZwArhj4VAfJ_K/view?usp=sharing


End file.
